Inconsistent first layers after first few prints
Hi everyone,
I'm relatively new to 3D printing and recently bought a second-hand Prusa MK3S+. Initially, I managed to get it running quite well, but now I can’t even get it properly leveled anymore.
After buying it, I installed a brand-new hotend and 0.4 mm nozzle. I went through the calibration assistant and, after a few tries, got everything dialed in. I successfully printed three Multiboard tiles in a row. Then I moved the printer from the living room to the basement and printed another Multiboard tile without any issues.
But then everything went crazy — the next print failed with spaghetti and a filament blob.
I cleaned the hotend and performed several cold pulls, but still couldn’t get the first layer to stick properly. Every test print ended in a blob. I disassembled the hotend again, cleaned it thoroughly, and reassembled it. When I reran the calibration assistant, it reported loose belt pulleys. I tightened them using the belt tuning app and then reran the full calibration, including Z-leveling.
I then tried the “Stress-Free First Layer Calibration in Less Than 5 Minutes” model from Printables and printed three of those calibration patterns without changing anything in between. The results (see attached pictures) are not consistent at all. Shouldn’t the test prints look identical at the same Z, if I didn’t change anything?
What could cause these inconsistencies? What else should I check?
The most frustrating thing is that I had the printer working just fine at first— and then, suddenly, it stopped working consistently. I suspect the main issue might be the person sitting in front of the printer 😉, but honestly — I’m out of ideas.
Any help or suggestions would be greatly appreciated!
RE:
After moving a printer it's always worth running an XYZ calibration: https://help.prusa3d.com/article/xyz-calibration-mk3-mk3s-mk3s_112351
And it is possible (not probable) that your print bed is off level so: https://help.prusa3d.com/article/bed-level-correction_2267
In addition there are signs of fingerprints on the print sheet so a thorough clean will help.
Cheerio,
RE: Inconsistent first layers after first few prints
After I moved the printer to the basement, it actually completed the first print perfectly fine. So I assumed everything was okay.
Anyway, after cleaning the entire hotend, I ran the calibration wizard (I just realized it is called “wizard” in English, not “assistant”, sorry for the confusion). During that run it reported the loose belt pulleys. After fixing them I ran the calibration wizard again. So that should not have been the issue.
I am not sure what fingerprints you are seeing on the print sheet. I clean it with 99,9 % isopropyl alcohol every time. The only area I touched was the bottom right corner (-1,420), but that was after the print had already finished, so it should not have affected the print on the rest of the sheet.
Today I did a full XYZ calibration again, followed by a first layer calibration. That resulted in a Z value of - 1.450 mm.
So I did the other test prints and this is inconsistent again.
The first one (-1.420 to -1.460) was clearly too high (even though the first layer test print was really good at -1.450 mm).
The second one (-1.450 to -1.490) is a little better, but the -1.450 does not show the same amount of separation as on the first print. But should that not be the same? And finally, the third test print (-1.480 to -1.520) is pretty good all over. How come the setting of -1.480 mm is so different between the second and third print? I did not change anything between those two prints.
I did not even start the bed level correction yet, since I cannot even get the Z value right.
RE: Inconsistent first layers after first few prints
This last week I tried everything I could think of -as a novice- or google to solve my first layer issue. I checked the belts, all the screws I could find, ran the calibration wizard multiple times, ran the XYZ calibration multiple times on top of that, scrubbed the print sheet with dish soap and a scrub sponge, scrubbed it with acetone, scrubbed it with dish soap again, cleaned it with 99,9% isopropyl alcohol, set the mesh bed leveling to [7x7],.... I still can't get a consistent first layer.
The best test result so fas is a simple test print at a live-adjust-Z of -1,490 mm. However, when I do a 3x3 test print with the same Z, the lines in the middle are clearly separated, which I interpret as the nozzle being too far from the sheet. Why is there such a difference between two different print patterns, when I did not change anything else?
Currently I am using up all my filament and time with the test prints instead of printing what I need. But I do not want to get started on the real prints, if I don't have the first layer set properly yet.